A Short Proof for a Lower Bound on the Zero Forcing Number

We provide a short proof of a conjecture of Davila and Kenter concerning a lower bound on the zero forcing number Z(G) of a graph G. More specifically, we show that Z(G) ≥ (g − 2)(δ − 2) + 2 for every graph G of girth g at least 3 and minimum degree δ at least 2